Luminaire



A. DE BISHOP, JR

LUMINAIRE Filed Feb. 24, 1944 2 Sheets-Sheet 1 mvzgron ARTHUR 0s lsHaPmBY ATTORNEY Feb. 24, 1943.

A. DE BISHOP, JR I 2,436,635 LUMINAIRE Filed Feb; .24, 1944 2 Sheets-Sheet'2 mvsmon lkmuk DE BISHOP J5.

ATTORNEY Patented Feb. 24, 1948 I UNITED STATES PATENT OFFICE Arthur DeBishop, Jr., Southington,

Conn alsignor to The Donne Products Corporation,

Meriden, Conn,

a corporation of Connecticut The present invention relates toluminaires, and is more particularly directed toward direct lightitbeingunderstood that the drawings are illusing luminaires employingsuperposed fluorescent V lamps received between downwardly actingreflectors, and these luminaires preferably have luminous side walls.

The present invention contemplates fluorescent lighting luminaireswherein the lamps are in pairs and one above the other and received inopen mouthed reflectors such that except for reflection losses all ofthe light emitted by the lower lamp and the half of the upper lamp belowthe center of that lamp escapes out of the mouth of the reflector asdirect or reflected light, while the light originating in the upper partof the upper lamp is largely utilized tor either lighting translucentside walls of the luminaire or for indirect lighting.

The present invention relates to improvements over the luminaires ofDoane Patent 2,240,179.

Where the invention is embodied in two-lamp luminaires it iscontemplated that the luminaires will be symmetrical with respect to amedian 1ongitudinal plane through the centers of the lamps and thereflectors terminate at or close to the plane through the center of theupper lamp. Sucha construction uses less material than that of theformer patent in luminairesof a comparable lamps size and has a wellcontrolled dominant output for direct lighting and either an indirectcomponent or, luminous side walls which improve its appearance and lightup adjacent ceiling areas.

Where the invention is embodied in four-lamp luminaires, it iscontemplated that the luminaire will be symmetrical with respect to acentral medial plane and have two pairs of lamps on either side of thecentral plane and each pair of lamps is associated with downwardlyacting reflectors one of which terminates at or close to the plane ofthe center of the upper lamp, while the other reflector extends higherbut does not cross the vertical plane through the lamp centers and thebottoms of the latter reflectors meet at the center of the fixture. Sucha construction is similarly economical or material, has well controlleddominant output for direct lighting and the upwardly escaping light maybe allowed to go upwardly for indirect lighting or directed towardtranslucent side panels.

Other and further objectswill hereinafter ap pear as the descriptionproceeds.

The accompanying drawings show, for purposes of illustrating the presentinvention, several embodlments in which th invention may take form,

iii

trative oi the invention rather than limiting the same.

In these drawings:

Figures 1 and 2 are transverse sectional views through two-lampluminaires, Figure 1 showing an exposed luminaires mounted at or belowthe ceiling level, and Figure 2 showing a luminaire partly recessed;

Figures 3 and 4 are transverse sectional views through four-lampluminaires having luminous Side walls;

Figure 4a is a perspective view of the luminaire of Figure 4;

Figure 5 is a fragmentary sectional view of a pendent four-lampluminaire arranged for direct and indirect lighting;

Figure 5a is a perspective view of the luminaire of Figure 5; and

W Figure 6 is a sectional view of a pendent twolamp luminaire arrangedfor direct and indirect lighting.

For clarity and simplicity of the drawings lamp and starter sockets,wiring, supports and the like have been omitted, as' well as manystructural details which a complete luminaire would employ. Figure 1illustrates a luminaireadapted to be mounted in anexposed positioneither pendent or closeto the ceiling. The top wall of the lumlnaire isillustrated at to. This will generally be a metal wall painted whiteinside so as to provide a diffuse reflecting surface. The side walls orthe luminaire are indicated at I i, I l, and these are typicallylouvered or difiusing plastic sheet material, or glass. The bottom walll2 of the enclosure is preferably a louvered plastic sheet which permitsdirect transmission of light downwardly but limits the longitudinalspread. The framework of the enclosure includes-S-shaped metal channelsit at the top and channels at right angles to one another at the bottomcorners as indicated at i i, i l

Two fluorescent lamps are indicated at it and it. They are mounted onedirectly above the other and almost in contact. The reflectors 55, It,as shown in Figure 1, are alike and have their upper edges It, It closeto the upper lamp and at substantially the level of the center it ofthat lamp. The lower edges ll, ll of the reflectors are substantiallyone-half the lamp diameter below the lower lamp to provide a out onangle which .may vary, but is here indicated as being about 75 above thenadir, and hence the reflectors intercept light emitted laterally fromthe upper lamp below the plane through its center and from the lowerlamp, and allow a certain portion of the light from each lamp to escapeas direct light. The upper Portion la of the reflector I5 is designed toact on light from the lower lamp and reflect it downwardly at or nearthe vertical as indicated by theray 18-16: the intermediate portion 15bto downwardly reflect light from the closely adjacent surfaces of thelamps (which are brightest due to reflection of light on each lamp) atsteep angles as indicated by the ray til-l9; and the lower portion l5cto act on light from the lower lamp and reflect it back across themedial plan A-A so as to spread the rays widely, as shown by the rays20-20, 2l2l. The rays 22 from the upper lamp are reflected downwardly asindicated at 22' in more vertical angles than the widely spread rays26', 2|. Thus the employ-- merit of two lamps one above the other withtwo reflectors indicated makes it possible to obtain a lightdistribution which incorporates the high angle light typical ofextensive distribution and the vertical light typical of concentratingdistributions. The portions I511, I512 and 15c are typically asuccession of parabolic arcs with focal points at and above the centerI4 of the lower lamp with the axes tilting more and more from thevertical as will be obvious from the slope of the reflected rays.Typical axes are indicated by dot-and-dash lines [8a, "la and 20a. Thecurving contour could also be composed of a succession of circular orelliptical arcs.

The light which is emitted upwardly and to.

the lamp l3 directly to the translucent side wall,

as indicated at 26.

In the luminaire in Figure 2 the direct light is controlled in the samemanner as in Figure 1, but owing to the depth of the cover Illa of theluminaire and the shallowness of the side walls Ha the only light whichreaches these side walls is that reflected by the outside of thereflectors I5, as indicated by the rays 211.

The fixture shown in Figur 3 is symmetrical about a central median plane30, 36. The luminaire has a top wall 31, translucent side walls 32,32and a translucent bottom wall 33. It carries two pairs of fluorescentlamps 34, 35 arranged one above the other in vertical planes 36-36. Theportions of the luminaire beyond the planes 36-36 ar optically the sameas onehalf of the luminaire shown in Figure 1 and the same light controltakes place, as indicated by similarly disposed light rays. Between thepairs of lamps the lu mlnaire is provided with reflectors 31, 31 whichextend from the central plane 36, 30, near the bottom closure, upwardlyso as to come close to the outer surfaces of the upper lamps 34 atconsiderable distances above the plane through the centers 34' of theselamps. I'he reflectors extend up to and are secured to th cover or top31, as indicated at 38, 38. The

stepped contour indicated is merely for convenience in manufacture.

The reflectors 31, 31 are composed of parabolicthe upper lamp isintercepted and reflected down through the bottom of the enclosure. Thepaths of light rays are indicated by the lines 39, 39', 40, 40', 4|, 4|,42, 42' and 43, 43'. So tar as the control of the light emitted by thelamps below the plane through the center of the upper lamp is concerned,the two reflectors act substantially alike. For the down lighting fromeach pair of lamps the optics are symmetrical even though the structureis asymmetrical. The luminaire is much narrower than it would be if allfour of the reflectors were the size of the central reflectors.

If desired, the top of the luminaire of Figure 3 may be provided withopenings such as illustrated at 44 at the right, these openings havinglight transmitting covers 45 or not as desired so that a small indirectcomponent may be obtained. The space between the reflectors 31, 31 maybe employed to receive the ballast indicated at 46.

The lumlnalre 41 shown in Figures 4 and 4a employs the same arrangementof lamps and re- 1 flectors as indicated in Figure 3, and the samereference characters are employed. Instead of having the lower outsidecorners of the lumlnalre made up by channels ll'l I arranged at rightangles to one another as shown in Figures 1 and 3, the bottom wall 46 isbent upwardly and is received in an-S-shaped channel 48 which alsosupports the side panel ll. Its side walls II will be brighter due tolight reflected as indicated at 56.

The luminalre of Figure 5 employs the same pairs of lamps 34, 35 andreflectors l5 and 31 as in Figure 3. Instead, however, of having the topof the lumlnaire closed as in Figure 3, it is here left open so thatlight rays such as 5| from the upper lamp may escape upwardly withoutin. terference. Instead of having light transmitting side walls theluminaire is provided with reflecting side walls 52 which may be opaqueor translucent and are adapted to deflect light rays such as 53 upwardlyas indicated at 53. The bottom 54 is arranged to receive some light rayssuch as 55 and reflect them upwardly on to the outer surface of the sidewalls 52 as indicated at 56, so that these walls appear luminous.

Figure 6 shows a luminaire 60 embodying the same arrangement of lamps l3and I4 and reflectors l5, I5 as illustrated in Figures 1 and 2. Itemploys two reflectors 62, 62 similar to the reflectors 52 of Figure 5,and the bottom 63 of the .luminaire 60 is similar to the outer portionof the bottom 54 of the luminaire of Figure 5 so that in the luminairein Figure 6 part of the light escapes upwardly for indirect lighting andpart of it is diverted so as to illuminate the outer surfaces of thedeflectors 62.

The arrangements shown herein provide a well controlled dominant outputof light for direct lighting by reason of the use of the reflectorswhich avoid trapping or blocking all light from the top or the upperlamp, and make it possible to use the light from this part of the upperlamp either for illuminating translucent side walls of the luminaire orfor indirect lighting. It is possible to provide a four-lamp luminairewith reflectors for controlling the light output in an effective mannerwith desirable cutoff angles and yet not have the luminaire excessivelywide. For example, a luminaire such as illustrated in Figure 3 arrangedfor four 40 watt lamps may be about 13" wide.

Since it is obvious that the invention may be embodied in other formsand constructions within the scope of the claims, I wish it to beunderflected downwardly by stood that the particular forms shown are buta changes being possible, I do not otherwise limit myself in any waywith respect thereto.

What is claimed is:

1. In a luminaire, means for controlling the few of these forms, andvarious modifications and lower portions of the reflectors reflectinglight emitted laterally from the lower lamp across the median plane tospread the reflected light widely therefrom, the Upper portionreflecting upwardly emitted light from the lower lamp substantiallyvertically downward for concentrating light below the luminaire, thelight from the upper lamp being reflected downwardly at anglessubstantially move vertical than the widel -spread reflected light fromthe lower lamp, one of the reflectors terminating at substantially thelevel of the center of the upper lamp and close to its surface the otherreflector having greaterradii of curvature and extending above the planethrough the upper lamp center and close tothe surface of the upper lamp.

2. The combination with two horizontally extending tubular, rectilinearfluorescent lamps of the same diameter mounted one above the other andclose together, of a specular, inwardly concave reflector extendingoutwardly from close to the surface of the upper lamp at the level ofthe axis of the upper lamp so as to intercept direct light from thelower portion of the upper lamp and allow the escape upwardly of lightfrom the upper portion of the upper lamp, and alsoextending downwardlyso as to diverge from the median plane through the centers of the lampsand terminating substantially one-half the lamp diameter below thebottom of the lower lamp at an angle of substantially below the same soas to intercept low angle direct light from the upper lamp and directlight from the lower lamp between the upper lamp and the 75 oblique cutoff plane defined by the bottom of the lower lamp and the lower edge ofthe reflector, the upper portion of the reflector profile being at arelatively small angle below the horizontal to reflect light generallyvertically downward outside the lower lamp, the lower portion of thereflector profile being relatively steep and reflecting direct lightfrom both lamps across the median plane.

3. The structure of claim 2, having a second similar reflector similarlydisposed on, the opposite side ,of the median plane.

4. The combination claimed in claim 2, wherein the upper surface of thereflector is diffusing, and having an enclosure for the lamps andreflector, the enclosure having a light transmitting bottom fordownwardly emitted direct light and light reflected downwardly from thereflector, a translucent side wall which screens the reflector, and atop wall which reflects light downwardly onto the side wall and theupper surface of the reflector.

5. The combination claimed in claim 2, wherein the upper surface of thereflector is diffusing, and having an enclosure for the lamp andreflector, the enclosure having a light transmitting bottom for downwardemitted direct light and light rethe reflector, a top wall whichreflects light downwardly and outwardly.

upper lamp and the 75 and a translucent screen extending from the bottomto the top wall and intercepting direct and reflected light originatingin the portion of the upper lamp above the reflector.

6. The combination claimed in claim 2, and having a second inwardlyconcave, specular reflector on the other side of the median plane havingthe same cut oif angle but extending above the horizontal plane throughthe upper lamp axis to intercept a substantial portion of the upwardlyemitted light from the adjacent side of the upper lamp.

7. The combination claimed in claim 2, wherein the upper surface of thereflector is diffusing. and having a secondinwardly concave, specularreflector on the other side of the median plane having the same cut offangle but extending above the horizontal plane. through the upper lampaxis to intercept a substantial portion of the upwardly emitted lightfrom the adjacent side of the upper lamp, and an enclosure for the lampsand reflectors, the enclosure having alight transmitting bottom fordownwardly emitted direct light and light reflected downwardly from thereflectors, a translucent side wall which screens the first reflector,and a top wall which reflects light downwardly onto the side wall andthe upper surface of the first reflector.

8. The combination with two horizontally extending tubular, rectilinearfluorescent lamps of the same diameter mounted one above the other andclose together, of a specular reflector extending outwardly from closeto the surface of the upper lamp at the level of the axis of the upperlamp so as to intercept direct light from the lower portion of the upperlamp and allow the escape upwardly of light from the upper portion ofthe upper lamp, and also extending downwardly so as to diverge from themedian plane through the centers of the lamps and terminatingsubstantially one-half the'lamp diameter below the bottom of the lowerlamp and at an angle of substantially 15 below the same so as tointencept low angle direct light from the upper lamp and direct lightfrom the lower lamp between the oblique cut off plane defined by thebottom of the lower lamp and the lower edge of the reflector, the upperportion of the reflector being parabolic with its focus substantially atthe lower lamp center and its axis substantially vertical so as toreflect light generally vertically downward, the lower portion of thereflector being parabolic with its axis oblique and crossing the medianvertical plane so as to reflect light across the median plane.

9. The combination claimed in claim 8, having a second specularreflector on the other side of the median plane having an upperparabolic portion extending above the horizontal plane through the upperlamp axis and with its axis and focus substantially coincident with thatof the first mentioned upper portion and a lower inwardly concaveportion with the same cut on angle and a profile to reflect light fromthe lamps across the vertical median plane.

10. A fluorescent lighting luminaire symmetrical on opposite sides of amedian plane and having two pairs of fluorescent lamps, the lamps ofeach pair belngmounted one above the other and close together, innerupwardly andoutwardly diverging, downwardly acting, inwardly concave,specular reflectors extending from the median plane of the luminaire ata distance below the bottoms of the lower lamps so as to providepredetermined cut oil angles and having their upper the correspondingpair 01' lamps. and a pair of outer downwardly acting specularreflectors converging upwardly and inwardly from points below the lampsto provide the same cut oil angles and having their upper edges close tothe outer sides or the corresponding upper lamps above the horizontalplane through the adjacent upper lamp, the upper portion of each of theouter pair of reflectors being at relatively small angles below thehorizontal and reflecting light generally downward outside thecorresponding lower lamp, the lower portion of each oi the outerreflectors being relatively steep and reflecting light across thevertical plane through the corresponding pair of lamps.

ii. A lumlnalre such as claimed in claim 10, wherein the luminaire has atranslucent bottom below all the reflectors and lamps. a downwardlyreflecting top wall, and translucent side walls each illuminated bylight escaping from the adiacent upper lamps between the reflectorsterminating adjacent thereto.

ARTHUR DE BISHOP, J5.

REFERENCES CITED The following references are oi record in the die ofthis patent:

UNITED STATES PATENTS Number Name Date 2,240,179 Doane Apr. 29, 19412,258,354 Doane Oct, '7, 1941 2,291,493 Naysmith July 28, 1942 2,306,700Kantack i. Dec. 29, 1942 2,321,701 Potter June 15, 1943 2,337,437 AllenDec. 21, 1943

